cumshaw vs invitation

cumshaw

noun
  • A gratuity or tip as thanks for a service 

verb
  • To give or make a present to. 

invitation

noun
  • A document or verbal message conveying an invitation. 

  • The act of inviting; solicitation; the requesting of a person's company. 

  • A bid that tells one's partner that game or slam is likely if their hand is at the strong end of what they have indicated. 

  • Allurement; enticement. 

  • A line that is intentionally left open to encourage the opponent to attack. 

  • The brief exhortation introducing the confession in the Anglican communion-office. 

How often have the words cumshaw and invitation occurred in a corpus of books? (source: Google Ngram Viewer )